Testing for hepatitis B virus core antigen and e antigen may confer additional safety of donors' blood negative for heptitis B virus surface antigen.

Sir,

Viral hepatitis B (HBV) is a major worldwide public health concern as it can be readily transmitted through blood transfusion, especially when blood collection would be performed during the window period.[1] The specific serologic markers for HBV testing include the hepatitis B surface antigen (HBsAg) and hepatitis B e-antigen (HBeAg), and the antibodies to hepatitis B core antigen and e-antigen (anti-HBc and anti-HBe). Anti-HBc can be detected in people infected with HBV. HBeAg is associated with HBV infection and is found when there is active replication of virus.[2]

This study was performed to test the positivity of serological markers in the blood of donors negative for HBsAg. Hence, the current study, performed at Hospital Tengku Ampuan Afzan, Kuantan, Malaysia, was carried out to determine the prevalence of anti-HBc, HBeAg, and anti-HBe among blood donors negative for HBsAg to detect potentially infectious blood units, and to help in deciding whether supplemental testing may result in additional safety to blood products. MONOLISA enzyme assays (MONOLISA, Bio-RAD Laboratories, France) were utilized to test for anti-HBc, HBeAg, and anti-HBe antibodies.

Out of 208 HBsAg-negative blood samples, 20 samples (9.6%) were found to be anti-HBc reactive. All these 20 samples were also positive for anti-HBe and were negative for HBeAg [Tables 1 and 2]. Furthermore, the prevalence of positivity was found to be higher among regular donors compared with new donors [Table 3].

Table 1

The positive IgG anti-hepatitis B core antigen among samples of donors’ blood that had been tested negative for HBsAg

Table 2

Data collected from HBe antigen and HBeAb tests from anti-HBcT-positive samples

Table 3

A comparison between new and regular donors positive for anti-HBc IgG antibodies

Although exposure to HBV may be followed by full recovery, it is still advisable to defer these anti-HBc-positive donors, at least temporarily. Furthermore, it can be suggested that testing for anti-HBc be introduced routinely for all blood samples, especially in Asian countries where the prevalence of HBV infection is generally higher than that in European and North American countries.[3] The high frequency of post-transfusion hepatitis is apparently because HBsAg circulates at undetectable levels for current screening assays; hence, screening for anti-HBc antibody is necessary.[4] This will increase the safety and reduce the risk of disease transmission during blood transfusion; however, it has a drawback in that it may also lead to a sharp increase in the rejection rates and may be responsible for an increase in the total costs. Thus, such a screening program can be substantiated by long-term follow-up of donors deferred for this reason, to monitor them for viral loads and/or development of clinical disease.